Diamond drill bit



Jan. 16, 1940. cs. J. MAIER DIAMOND DRILL BIT Filed March 14, less INVENTOR, z'er,

Georyc BY 9 ATTORNEY. Y

Patented Jan. 16, 1940 DIAMOND DRILL BIT George J. Maier, New

York, N. Y., assignor to J. K. Smit 8.: Sons, Inc., New York, N. Y., a corporation of New York Application March 14, 1939, Serial No. 261,779

2 Claims.

This invention relates to abrasive devices and drill bits and methods for making them and more particularly to drill bits known as diamond or bortz drills, though it is noted that in some of the claims the invention is not limited to diamond or bortz drills nor even to drills.

One object of the invention is to provide an improved means and method for anchoring the diamonds or other abrasive elements to the body of the drill or other device.

Additional objects of the invention are to improve generally the simplicity and efiiciency of such methods and devices and to provide a simple abrasive device of this kind which is economical, durable and reliable in use and economical to manufacture.

Still other objects of the invention will appear as the description proceeds; and while herein details of the invention are described in the specification and some of the claims, the invention is not limited to these, since many and various changes may be made without departing from the scope of the invention as claimed in the broader claims.

The inventive features for the accomplishment of these and other objects are shown herein in connection with an improved drill bit which briefiy stated, includes a tubular holder provided in its lower end face with an annular groove 30 against which lower face a steel ring is disposed,

cooperating with said groove to form an annular chamber, said ring having small apertures therein communicating with said chamber and receiving elongated abrasive elements disposed in 35 and slightly projecting from said apertures. A metal body is cast in said chamber and apertures and around the abrasive elements, bonding them all together.

In making the drill bit the abrasive elements 40 are disposed in the apertures, and molten metal is passed into said chamber to cause the molten metal to pass into and harden in the chamber and apertures and around the abrasive elements, thus bonding the ring and elements, and in some cases the holder, together.

While herein, the holder and ring are mentioned as being of steel and the molten body and abrasive elements are respectively mentioned as being of bronze and diamond or bortz, it is understood that other suitable materials may be used, within the scope of the claims.

In the accompanying drawing showing, by way of example, several of many possible embodiments of the invention,

Fig. 1 is a fragmental side elevation showing one form of the invention;

Fig. 2 is a bottom plan of the drill of Fig. 1;

Fig. 3 is an enlarged transverse vertical sectional view, partly in elevation, showing the 6 apertured ring with the metal body bonding the abrasive elements in the apertures;

Fig. 4 is a fragmental vertical sectional view, partly in elevation, showing another form of the invention, partially completed and disposed on a plate for aiding in making the drill;

Fig. 5 is an enlarged bottom plan of the ring of Fig. 4;

Fig. 6 is a vertical sectional view, partly in elevation, showing the ring with apertures therein, the section being taken substantially on the line 6-6 of Fig. 5, looking in the direction of the arrows of said line;

Fig. 7 is an enlarged fragmental vertical sectional view, the section being taken through the holder, the ring and the cast metal body and showing abrasive elements in section; and

Fig. 8 is a sectional view similar to that of Fig. 4, but showing a modified form of the invention.

My improved drill bit of Figs. 1 to 3 comprises a tubular steel shank or other suitable holder l0 provided in its lower end face with an annular groove ll leaving inner and outer annular portions l2, l3 of the end face, the groove having a substantially vertical inner and outer faces.

A thin channel-shaped steel ring l5 of semicircular cross-section (Fig. 3) has its edges l6, l1 disposed against said annular portions I2, I3, the ring having small apertures l8 drilled downwardly radial to said crosssection and having their lower ends tapered, as left by the drills when the tapered end only of the drill penetrates the ring. Elongated diamonds, bortz or other abrasive elements 20 are disposed in said apertures slightly projecting at the bottom, if desired, and extending inwardly in the channel of the ring.

The ring is provided with large axially vertical bores 22 countersunk at the lower part which are axially alined with vertical threaded bores 23 provided in the holder, the bores receiving screws 24 having heads 25 inset in the countersunk ends, so that the heads do not project.

A bronze body 21 is cast in said channel, apertures, and around the diamonds and bonds the ring, the diamonds and body together, and

has at its upper part an annular projecting rib 28 fitting in said groove of the holder.

The round nosed drill bit of Figs. 1 to 3 may be made in a variety of ways. The ring with abrasive elements in the apertures as shown in Fig. 3 may be placed in a mold having a cavity therein shaped to provide the body 21 approximately as shown. The rib 28 may be machined after molding to accurately fit the groove l l. The bores 22, 23 and the screws 24 may be provided and assembled in usual known manner.

Another way of making the drill of Fig. 1 will be mentioned in connection with the drills of Figs. 4 to 8.

The fiat nosed drill bit of Figs. 4 to '7 comprises a tubular steel shank or holder 30 provided in its lower end face with an annular groove 3| leaving inner and outer annular portions of the end face 32, 33 (Fig. '7) and having a substantially vertical inner face 34 and an outwardly flaring outer face 35, which allows the passage of the drill 36 (Fig. 4) to provide inwardly upwardly inclined bores 31 from the interior of the groove 3| to the interior opening 38 of the tubular holder, the bores, as they emerge into said opening, being of reduced diameter, as at 39, as left by the drill in making them.

A steel ring 45 is disposed flat against said annular portions 32, 33, and has an inner diameter slightly less than the inner diameter of the holder, and is provided with downwardly drilled small apertures 48 passing through the upper and lower faces of the ring and having their lower ends 49 tapered as left by the drills. Elongated diamonds, bortz or other abrasive elements 50 are disposed in said apertures and slightly projecting at the bottom and extending to near the top of the apertures.

Said ring is provided with larger vertical bores 52, 53 countersunk at the lower end; and screws 54 are disposed in the bores 52 and received in threaded vertical bores in the holder to hold the ring in place, said screws having heads inset or flush in the countersunk ends. A bronze body 51 cast in said inclined bores 31, groove 3|, apertures 48, bores 53 and their countersunk ends and around the diamonds 5!], bonds the ring, the diamonds, the bronze and the holder together.

The bit of Fig. 8 is similar to that of Figs. 4 to '7, except that the outer diameter of the ring 45' is larger than that of the tubular holder 30 and has a slightly raised annular portion 46 surrounding the lower end of the holder. In addition to the apertures 48, said ring 45' has similar outwardly downwardly inclined apertures 48' communicating with the annular groove 3| and having diamonds 50 therein and bonded therein by bronze in the apertures integral with the aze in the groove.

ihe rings of Figs. 4 to 8 may be made in a variety of ways. The abrasive elements may be inserted from the top or the bottom of the apertures 48, 48'; but if the elements are larger at the upper part than the lower diameter of the apertures, they are inserted at the top. In this latter case, the workman places under the ring 45, a plate 60 having shallow recesses 6| registering with said apertures 48. Then the diamonds are placed in the apertures and project slightly into the recesses 6|. Then the holder 30, ring 45 and said screws 54 are assembled with the ring tight against said faces 32, 33 and all are disposed in upright position with said plate beneath, as illustrated in Fig. 4 the recesses a1- lowing the diamonds to project slightly and to be held in projecting position.

If the abrasive elements are inserted through the outer or lower ends of the apertures, the holder, ring and screws may be assembled first, and the assembly placed upside down for the insertion of the elements, after which the plate 60 is placed over the ring, and the whole turned right side up, the abrasive elements then being allowed to'project into the recesses 6|.

In either case, after the assembly is placed right side up upon the plate 6|], a disk 63 of carbon or other suitable material is placed in said opening 38, and on said ring, just below the inner end of the inclined bores 31. The assembly is heated if necessary to prevent too quick chilling of molten bronze which is then poured into said opening 38 and, if desired, subjected to air pressure or centrifugation to cause the molten metal to pass into and harden in the bores 31, 53, groove, countersinks and apertures and around the diamonds, thus bonding them all together. The disk 63 may be removed before the metal thereon has fully hardened; and the excess bronze may be removed by any suitable tool or machine.

When the molten metal hardens, it shrinks, causing the metal in the countersunk bores 53 to shrink and draw the steel ring tightly against the holder.

The screws 64 may be omitted, if desired, as metal in the countersunk bores 52, 53 is suflicient for holding the ring in place. On the other hand, the screws alone may be used if desired.

The bit of Figs. 1 to 3 may be made by a method similar to that of Figs. 4 to 8, in which case the ring l5 and diamonds 20 may be assembled in a mold, as first stated, with the holder 20 placed upon the ring. The metal can be entered through bores in the holder I0 similar to the bores 31 of the holder 3|].

The invention claimed is:

1. A drill bit comprising a tubular holder provided in its lower end face with an annular groove, 2. channel shaped steel ring disposed against said lower face and cooperating with said groove to form an annular chamber; said ring having small apertures therein communicating with said chamber, the outer ends of said apertures being tapered; elongated abrasive elements disposed in and slightly projecting from said apertures; and a metal body in said chamber and apertures, and cast around the abrasive elements to bond the holder, the steel ring and abrasives together.

2. A drill bit comprising a tubular holder provided in its lower end face with an annular groove leaving inner and outer annular portions of th end face; a channel shaped steel ring having its edges disposed against said annular portions and having small apertures therein, the outer ends of said apertures being tapered; elongated abrasive elements disposed in said apertures slightly projecting at the bottom and extending into the channel of the ring; screws for securing said ring to the holder; and a metal body cast in said channel and apertures, and around the elements, bonding the ring, the elements and body together; said body having at its upper part an annular projecting rib fitting in said groove of the holder.

GEORGE J. MAIER. 

